An Upper Physical layer functional Split (UPS) for an Ethernet fronthaul network is modelled, and the frame delay and Frame Delay Variation (FDV) limitations are investigated. The results show that contention in Ethernet switch ports can cause an increase in the delay and FDV beyond proposed specifications for the UPS and other time-sensitive traffic types such as I/Q-type traffic. Time Aware Shaping

Elastic Optical Networks (EONs) are extensively accepted promising solution for future ultra-high-speed optical transmission, due to their capability of efficient and flexible assignment of immense optical bandwidth to the heterogeneous traffic demand. However, it undergoes through an aggravated form of the spectrum fragmentation problem due to the heterogeneous bandwidth requirements, spectrum continuity

This paper proposes a static Routing and Spectrum Allocation (RSA) method to design low-power elastic optical networks. In the elastic optical networks, data are transmitted via lightpaths, which are routes flexibly assigned frequency resources according to transmission distances and traffic demands. When designing the elastic optical networks with a static lightpath establishment policy, lightpaths

Advanced modulation formats like dual-polarization quadrature phase-shift keying (DP-QPSK) along with the digital coherent receiver are enabling optical networks to provide high spectral efficiency (SE) over long-haul transmission reach. The DP-QPSK based dense wavelength division multiplexing (DWDM) system with 37.5 GHz channel spacing can provide extra throughput of 33% compared to 50 GHz channel

The proposed adaptive power control based on the chaotic hurricane search optimization (A-CHSO) for elastic optical networks (EON)s dynamically and efficiently adjusts the power increasing (r0) parameter taking into account the quality of transmission (QoT), which is measured by the optical performance monitors (OPM)s. For sake of comparison, three alternative power assignment methods are analyzed

As optical fibre reaches deeper into passive optical network (PON) in fibre-to-the-x (FTTx) networks, maintaining the integrity of these networks is indeed imperative. Essentially, best practices have been established throughout the installation and verification of the fibre access network. Equally significant is monitoring the optical fibre performance degradation in-service to ascertain efficient

Based on software defined optical network and machine learning, the flexible resource management mechanism (ML-FRM) is proposed, which meets the resource requirements of different services in the optical data center networks. The machine learning is integrated to the SDON controller, which accomplishes the resource allocation algorithms according to the classification and clustering results. ML-FRM

Passive optical networks (PONs) are the most successful broadband access solutions for its wide bandwidth, low-cost deployment worldwide, and maintenance. In the last decade, the diverse and prevalent research related to PONs sustains 330+ science citation index (SCI) articles per year, with 9.18 average citations per article, making it "big literature data". This article, for the first time, presents

Elastic Optical Networks (EONs) allow the channel spacing and the spectral width of an optical signal to be dynamically adjusted and hence have become an important paradigm in managing the heterogeneous bandwidth demands of optical backbone networks. The entire available optical spectrum is divided into some spectrum slots which define the smallest granularity of bandwidth and optical signals with

Today's optical transport networks are complex already and the support of the new arising services will further increase such complexity. Traditional deterministic network procedures will need to be revisited, especially their operations. Network Operators will require more dynamic approaches to get the best out of their infrastructure. In this context, cognition and machine learning techniques can

Elastic Optical Networks (EON) emerge as a viable solution to support the current growing demand for bandwidth. With the application of multi-core fibers (MCF) in EON links, it is possible to increase the availability of spectral resources and explore the spatial dimension. An EON network with MCF enables Space-Division Multiplexing (SDM), allowing the use of more resources in fibers and increasing

Application-centric networking proposes a novel approach to provision connectivity services in transport networks based on application-specific requirements. By exploiting this paradigm, an application can request a service with several requirements to a generic control and management plane, which can leverage this information to differentiate a service on the overall network layers. However, an application-centric

In this paper, we concentrate on the comparison of different switching policies, as well as their corresponding spatially-spectrally flexible super-channel transmission technologies, in static SDM-EONs. These switching policies are different due to their different spatial switching granularities and/or whether the space lane change (SLC) is supported. According to our simulation results, the switching

In this paper, we focus on dynamic lightpath provisioning in translucent spectrally spatially flexible optical networks (SS-FONs) created with a combination of both spectral (EON) and spatial (SDM) flexibility. We utilize the distance-adaptive transmission (DAT) in order to select a modulation for request and routing path in a flexible manner. Moreover, we assume that the signal regeneration is realized

Underwater Optical Wireless Communication (UOWC) is a high-speed data transmission technology promising to support the concept of the Internet of Underwater Things (IoUT). The performance of UOWC-based IoUT networks, especially medium access control (MAC), could be affected significantly by physical factors in the underwater environment. However, there is a lack of studies on the MAC performance analysis

Elastic optical network has recently been deemed as a promising infrastructure to support the ever-increasing bandwidth demand of emerging applications, due to its high transmission rate, fine-grained and flexible spectrum allocation. With the explosive growth of traffic, optimizing energy and spectrum efficiency has become a critical issue for green elastic optical networks, which is closely related

This paper presents five approaches to solve the problem of finding the optimal backup resource assignment which maximizes the survival probability of network functions of middleboxes. In the previous work, no mathematical model to solve this problem is provided, so we formulate the problem as a mixed-integer linear programming (MILP) problem as the first approach. Formulating this MILP problem includes

One of the newest technologies to qualify transmission capacity of optical backbone networks is Space Division Multiplexing with Elastic Optical Networks (SDM-EONs). SDM-EON has the feasibility to add flexibility to Wavelength division Multiplexing (WDM) networks. In SDM-EON, connections can be setup more efficiently than WDM networks and EON without SDM. There are challenging issues in SDM-EON as

Emerging applications such as remotely-controlled human-to-machine and tactile-haptic applications in the Internet evolution demand stringent low-latency transmission. In realising these applications, current communication networks need to reduce their latency towards a millisecond order. In our previous study, we exploited supervised learning-based machine learning techniques in analysing and optimising

The rise of emerging services has brought a rapid growth in bulk data transfers across inter-datacenter (DC) wide area networks (WANs). To accommodate the demands of such services, DC storage is introduced into the data-plane path so that delay-tolerant bulk data can be temporarily stored and forwarded (SnF) when network is less busy. However, the use of storage transforms a conventional routing problem

In this study, we evaluate the operation of the Converting-Space-Converting switching fabric architecture. The investigated switching fabric is suitable for all kinds of slot-operating switches, no matters the slots are wavelengths, time, or others. The switching fabric is evaluated in terms of the number of slots in the interstage links and the blocking probability. In the evaluation process, we used

Passive optical star networks have attractive properties for multicast traffic in data centres, but are limited in transmission bandwidth per node due to sharing a finite total throughput capacity. By adding reconfigurable switching elements to the core of an optical star topology, simulations show that the expected transmission rate per node can be increased by 26–40% (at 90% and 70% network load

This paper proposes a virtual network function placement and routing model for multicast service chaining based on merging multiple service paths (MSC-M). The multicast service chaining (MSC) is used for providing a network-virtualization based multicast service. The MSC sets up a multicast path, which connects a source node and multiple destination nodes. Virtual network functions (VNFs) are placed

This article presents simulation studies of elastic optical switching fabrics. Simulation experiments were conducted using the software developed by the authors. The simulator allows one to determine the loss probability for individual traffic classes offered to a single optical network node. The node architecture of elastic optical networks is based on the structure of the 3-stage Clos switching fabric

In this work, different heuristic and optimization algorithms are proposed for downstream wavelength scheduling in ring-based WDM-PON mobile backhaul networks, where optical networking units (ONUs) are integrated with base stations (BSs). The main objective of this work is to improve the time delay of the packet delivery from the infrastructure to the end-users for both fixed and wireless traffic.

A novel scheme for high-reliability optical process level network (OPLN) with all-optical passive edge nodes in smart substation is first proposed, supporting both sampled value and generic object oriented substation event services with multicast traffic pattern. The edge node consists of n passive optical distribution modules and one arrayed waveguide grating, realizing the all-optical interconnection

Nowadays networks are the basis of our communication providing a great number of services. As a consequence, the traffic is increasing and there is a growing demand for new services that require stringent constraints on capacity, latency and jitter to provide an appropriate Quality of Service (QoS) to end users. In order to cope with these requirements, network infrastructure needs to evolve from a

We propose a methodology for planning TWDM-PON that combines three lines of approach, known from literature, into a single approach that establishes a trade-off among them. That may support the network designer in finding a solution that can, simultaneously, meet high bandwidth demands, keep assurance of quality of service (QoS) level agreed with users, and increase energy saving of the network by

A light trail in a WDM optical network is an optical communication channel that allows intermediate nodes to access the channel providing the flexibility for multiplexing traffic of multiple connections into the optical communication channel at intermediate nodes. The technique of multiplexing traffic of multiple connections into a single communication channel is known as traffic grooming. This paper

This paper proposes combining the augmented Lagrangian method (ALM) with evolutionary heuristic methods, as well as quasi-Newton optimization methods applied to the energy efficiency (EE) maximization in the optical code division multiple access (OCDMA) communication network. The particle swarm optimization (PSO) and a hybridization between the PSO and the gravitational search algorithm (GSA) called

Double-link failure models, in which any two links in the network fail in an arbitrary order, are becoming critical in survivable optical network designs. Optical networks that are over-dimensioned and purposely preplanned for full protection against any single-link failure may not survive well in an event of a double-link failure. It is therefore important to understand how much impact a subsequent

In optical packet/burst switched networks fiber loops provide a viable and compact means of contention resolution. For fixed size packets it is known that a basic void-avoiding schedule (VAS) can vastly outperform a more classical pre-reservation algorithm as FCFS. For the setting of a uniform distributed packet size and a restricted buffer size we proposed two novel forward-looking algorithms, WAS

With the development of passive optical network (PON), multiple PON systems using various multiplexing technologies can coexist. Virtualization technology is a preferable solution for multi-standard coexistence. In this paper, (max-min model)-based mode-matched algorithm is proposed in multisystem-based virtual passive optical network (VPON). By constructing a bipartite graph of the subsystems, a mode-matched

This article gives an insight on the importance to assign a different capacity to each network link and to tighten the Quality of Service (QoS) provision in the network, in dynamic WDM Optical Networks with wavelength continuity constraints. In the text, several examples illustrate the performance of different strategies. The usual procedure to compute the number of wavelengths of each network link

By introducing storage into Optical Circuit Switched (OCS) networks and storing delay-tolerant requests until off-peak hours, the networks can have better performance. Since scheduling a data transfer in SnF networks has to deal with the spatial and temporal arrangement of the request, it is much more complicated than the routing-alone problem. In our prior research, we proposed TS-MLG, a holistic

Most of today's cloud applications are delivered by Cloud Service Providers (CSPs) on top of a physical network managed by one or multiple Infrastructure Providers (InPs). This new way of delivering services is impacting InPs' revenues, as InPs are only responsible for transporting data to users. Network Function Virtualization (NFV) was proposed to help InPs gain more flexibility in provisioning new

This paper presents heuristics based on FIPP p-cycle as a solution for the protection problem in elastic optical networks. The proposed algorithms employ failure independent path protecting p-cycle (FIPP). The algorithms differ by the protection of either one or two simultaneous failure as well as by the employment of traffic grooming and spectrum overlap. An integer linear programming (ILP) is formulated

Mixed-line-rate wavelength division multiplexing (WDM) networks with discrete channel spacing generalize the fixed grid WDM networks and can support mixed-electronic-optical grooming efficiently. For optical transport networks with beyond 100 Gbps containers, optical layer grooming is needed to take full advantage of variable grid spacing, as well as to improve spectrum utilization. In this work, we

This work proposes a new regenerator allocation algorithm, named Circuit Invigorating Regenerators Assignment (CIRA) algorithm. The CIRA selects the regenerators to be allocated and adapts the modulation format applied to the circuit. Strengthening the circuit reduces the interference caused by the new circuits that will be established, leading to the reduction of circuit blocking in the network. Simulations

The most effective way of providing popular user services such as high-definition television, video conferencing and distributed gaming over the Internet is multicasting. Protecting multicast sessions against single link failure or a fiber cut in the WDM optical backbone is thus vital. Protection schemes involve reserving resources for backup paths that remain idle during normal fault-free operation

Visible Light Communication (VLC) uses lamps light to convey information. As such, lamps in VLC systems work not only as illumination devices, but as VLC Access Points (VAPs) as well. This makes the choice of the lamps’ specifications and positions vital to satisfy the illumination and communication requirements. It is important that an indoor environment has the best possible VLC performance and the

Optical interconnect can provide high bandwidth and low latency, which is considered as a good candidate for future multicore systems. To maintain the scalability of optical networks and simultaneously support high performance communication, we propose a Statistical Multiplexing Optical Network-on-Chip (SMONoC), a new architecture targeting dynamic channel allocation for high channel utilization, a

Fragmentation in Elastic Optical Networks is an issue caused by isolated, non-aligned, and non-contiguous frequency slots that cannot be used to allocate new connection requests to the network, due to the optical layer restrictions imposed to the Routing and Spectrum Assignment (RSA) algorithms. To deal with this issue, several studies on Spectrum Defragmentation have already been presented. In this

This paper introduces the Multi-Server Multicast (MSM) approach for Content Delivery Networks (CDNs) delivering services offered by a set of Data Centers (DCs). All DCs offer the same services. The network is an Elastic Optical Network (EON) and for a good performance, routing is performed directly at the optical layer. Optical switches have heterogeneous capacities, that is, light splitting is not

In elastic optical networks (EONs) employing weakly coupled single-mode multi-core fibers (MCFs), inter-core crosstalk (XT) can affect significantly the network performance, particularly when the number of cores and the path length increase. Hence, from the network perspective, the impairment-aware routing, spectrum and core assignment (IA-RSCA) problem is the most important concern of MCF-EONs. In

Many multiplexing technologies have been proposed to meet the need for high network capacity. One can foresee that transmission systems with many multiplexing levels will be used in telecommunication networks in the future, and the need for switching connections to pass through multiplexed fiber links will rise accordingly. One Clos-like network with k multiplexing levels was proposed in an earlier

This editorial introduces the topic area of this special issue, namely the area of Software Defined Networking (SDN) controlled optical transport networks, i.e., so-called transport SDN (T-SDN) networks, that support emerging fifth generation (5G) wireless networks. We first outline the SDN concept and the main challenges and potential benefits of SDN control in optical transport networks. We then

Elastic Optical Networks have been the most promising technology in the next generation of transport networks due to their flexibility of spectrum assignment. Routing and spectrum assignment is one of their key issues. Several routing and spectrum assignment algorithms have been introduced in recent years. In this research, we propose a novel spectrum assignment algorithm called constrained-lower-indexed-block

This paper focuses on the performance improvement criteria suitable for WDM networks. Especially, an efficient resource allocation mechanism is introduced which organizes the number of data wavelengths into sets. Additionally, an effective access algorithm is applied by all stations in a decentralized way for the transmission over the data wavelengths sets, taking into account the receiver collisions

Exponential growth of traffic and bandwidth demands in current data center networks requires low-latency high-throughput interconnection networks, considering power consumption. By considering growth of both multicast and unicast applications, power efficient communication becomes one of the main design challenges in today's data center networks. Addressing these demands, optical networks suggest several

The combination of free space optic (FSO) and unmanned aerial vehicle (UAV) can be a promising solution to last-mile problem because of FSO high bandwidth and flexibility of UAV. However, FSO is vulnerable to the atmospheric turbulence and transmitter configuration is limited on UAV. Therefore, in this paper, we investigate an adaptive resource allocation strategy to provide relative fair and high

The elastic optical network is one of the emerging technologies in the optical network paradigm, and it has been highlighted by many researchers in the past few years. So far, a comprehensive study has been conducted on routing and spectrum assignment in elastic optical networks. However, only a few works considered the problem of failure, protection, and recovery to enable seamless data transportation

It has been proved that, in networks with co-existing delay sensitive and delay tolerant traffic flows, the overall network utility can be significantly improved by putting off (or storing) delay tolerant flows until off-peak hours. In our previous work, we proposed Time-Shifted Multilayer Graph (TS-MLG), a routing framework for Store-and-Forward (SnF) optical circuit switched (OCS) networks. With

Software-defined datacenters (SDDCs) have recently received much attention for rapid delivery of cloud-based applications. In this paper, we consider the design of an optical aggregation network for cost-efficient software-defined datacenters (SDDCs). Here, an optical aggregation network connects a server accommodating virtual network functions (VNFs) with access gateway nodes (AGNs) via a time-division-multiplexing

Optical interconnection networks have the potential to reduce latency and power consumption while increasing the bisection bandwidth of data center networks compared to electrical network architectures. Optical circuit-switched networking has been proposed but it is reconfigurable in milliseconds. Although switches operating on nanosecond timescales have been demonstrated, centrally scheduling such

FSO (Free Space Optics) is a well established wireless optical transmission technology considered as an alternative to radio communications, for example in metropolitan wireless mesh networks. An FSO link is established by means of a laser beam connecting the transmitter and the receiver placed in the line of sight. A major disadvantage of FSO links (with respect to fiber links) is their sensitivity

Automating the provisioning of 5G services, deployed over a heterogeneous infrastructure (in terms of domains, technologies, and management platforms), remains a complex task, yet driven by the constant need to provide end-to-end connections at network slices at reducing costs and service deployment time. At the same time, such services are increasingly conceived around interconnected functions and

Boolean network tomography can limit optical nodes on which electronic monitors need to be placed in all-optical mesh networks. However, required monitoring cost for operation and deployment increases as the number of optical nodes equipped with the electronic monitors decreases. The required monitoring cost depends heavily on the length of configured all-optical monitoring trails. Two heuristic approaches

The need for high data rates in telecommunications requires the constant search for improvements in these systems, especially in minimizing spectrum idleness in optical network. Currently, a solution to this issue is the elastic optical network, leading to numerous studies on the topic. As such, this article presents a study on elastic optical network, which considers physical layer effects (ASE noise

With the development of passive optical network, different standards will occur in the same network topology. Virtualization technology is a preferable solution for multi-standard coexistence. In this paper, priority-based mode transformation algorithm is proposed for cross-standard bandwidth management in multisystem-based virtual passive optical network (VPON) in metro-access optical network (MAON)